FOSSILS OF NEW JERSEY
Extinct Early Mako
Age - Eocene Commonality - Uncommon
One of several species of mako shark
teeth found in New Jersey, Isurus praecursor is the earliest known mako
and is restricted to the Eocene. Size is between ½ to 1 ½ inches long, the
teeth of I. praecursor, when
compared to the other makos has a relatively short stout crown. A nutrient grove is lacking, or a
best shows as a weak depression. On specimens that are not too stream
worn nutrient pores may be present, these may form what looks like a
single opening due to clustering and/or stream wear. Kent
mentions that the “lateral teeth of I. praecursor are nearly
indistinguishable from those of the later Isurus species”.¹ Most
reference material notes the similarity between these two species and
as an aid to identification. Large
sand tigers that are missing their cusplets may be mistaken for makos.
I. praecursor anterior lateral (top) and lateral (bottom).
One of my larger makos.
may be present on the lateral teeth.
Nutrient pore on an anterior tooth.
¹ Kent, W.B, 1994. Fossil Sharks of the Chesapeake Bay
Region, Egan Rees & Boyd, Inc., 57pp.